The mass of 800cm3 of gas Q at s.t.p. is 1.0g. What is the molar mass of Q? [Avogadros constant = 22.4dm3 mol-1`]

  • A 18.0 gmol-1
  • B 22,4gmol-1
  • C 28.0gmol-1
  • D 36.0 gmol-1
waec 2014chemistry

The correct answer is C. 28.0gmol-1

Imole Q occupies 22400 cm3

x mole occupies 800 cm3

x = \(\frac{800 x 1}{22400}\)

= 0.036mol

Molar mass = Mass Ã· Mole 

                    = 1 Ã· 0.036

 Molar mass â‰ˆ 28 g/mol

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